如何将 ARGB 值绑定到组合框项中的矩形填充属性？

Posted 2023-04-12

【中文标题】如何将 ARGB 值绑定到组合框项中的矩形填充属性？

【英文标题】：How do I bind ARGB values to a rectangle fill property in a combo box item?

【发布时间】：2019-07-19 03:51:53

【问题描述】：

我有一个自定义对象的组合框，每个对象都显示为一个彩色矩形，旁边是一个文本。

我有想要从对象显示的 ARGB 值，但我想将其转换为颜色并将其设置为矩形的填充属性。到目前为止，我有以下基于这篇文章 Binding R G B properties of color in wpf

如何指定 SubCategory 中的哪个属性传递给值转换器？以及如何将转换器的结果设置为矩形的Fill属性？

//XAML

<Controls:MetroWindow.Resources>
    <local:ArgbConverter x:Key="argbConverter"></local:ArgbConverter>
</Controls:MetroWindow.Resources>

<ComboBox ItemsSource="Binding Path=SubCategories" HorizontalAlignment="Stretch" SelectedItem="Binding Path=SelectedSubCategory, Mode=TwoWay" IsEditable="False" TextBoxBase.TextChanged="SubCategory_ComboBox_TextChanged">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <Rectangle Fill="Aqua"  Width="16" Height="16" Margin="0,2,5,2" ></Rectangle>
                <TextBlock Text="Binding Path=name, Mode=TwoWay" />
            </StackPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

//值转换器

public class ArgbConverter : IMultiValueConverter

    #region IMultiValueConverter Members

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    
        var a = System.Convert.ToByte(values[0]);
        var r = System.Convert.ToByte(values[1]);
        var g = System.Convert.ToByte(values[2]);
        var b = System.Convert.ToByte(values[3]);

        return new Color()  A = a, B = b, R = r, G = g ;
    

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    
        throw new NotImplementedException();
    

    #endregion

//视图模型

public ObservableCollection<SubCategory> SubCategories  get; set;  = new ObservableCollection<SubCategory>()  new SubCategory()  name = "person"  ;

//子类别类

public class SubCategory

    //default values - each of these objects will have different argb values
    public int A  get; set;  = 95;
    public int R  get; set;  = 225;
    public int G  get; set;  = 80;
    public int B  get; set;  = 25;

    public string name  get; set; 

【参考方案1】：

为什么不能使用IValueConverter 而不是IMultiValueConverter？

XAML

<Rectangle Fill="Binding Path=., Converter=StaticResource argbConverter" 
           Width="16" Height="16"/>

转换器

public class ArgbConverter : IValueConverter

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    
        var item = value as SubCategory;
        var a = System.Convert.ToByte(item.A);
        var r = System.Convert.ToByte(item.R);
        var g = System.Convert.ToByte(item.G);
        var b = System.Convert.ToByte(item.B);

        return new SolidColorBrush(new Color()  A = a, B = b, R = r, G = g );
    

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    
        throw new NotImplementedException();
    

【参考方案2】：

您已经实现了一个 IMultiValueConverter。所以显而易见的答案似乎是MultiBinding，有四个绑定到A、R、G和B属性：

<Rectangle>
    <Rectangle.Fill>
        <SolidColorBrush>
            <SolidColorBrush.Color>
                <MultiBinding Converter="StaticResource argbConverter">
                    <Binding Path="A"/>
                    <Binding Path="R"/>
                    <Binding Path="G"/>
                    <Binding Path="B"/>
                </MultiBinding>
            </SolidColorBrush.Color>
        </SolidColorBrush>
    </Rectangle.Fill>
</Rectangle>